Phasing sectional gang potentiometer



Nov. 4, 1958 F. H. mu es PHASING SECTIONAL GANG POTENTIOMETER Filed May5, 1956 JNVENTOR.

FRED H. KARG BY Z ATTORNEY v om mw 8 ww om mm mw o. w mm mv N mum aw wvm mm 6 5 n 5 om om mm 9 Q S Q t w on W aw PM .2 3 8 3 WM 2 9 m: .2 8 o2 am gm 2 mm m) 3 Q H IIMIW, I -iI 1 l4 I 41 HHHH i i, ill m. In 1 i 4id x: r x 2 1 rmm mm fi. mm 3 1 a g a illill 1i Q 5 I! 1 f 9 I .V -V 1mm WV. 0 Y \w nv mv mv m United States Patent 'Oihce PHASING SECTIONALGANG POTENTIOMETER Fred H. Karg, Burbank, Calif., assignor to ToppIndusgries Inc., Los Angeles, Calili, a corporation of CaliormaApplication May 3, 1956, Serial No. 582,373

6 Claims. (Cl. 20163) This invention relates to potentiometers and hasas its general object to provide a novel and improved potentiometerconstruction wherein a plurality of potentiometer units are connectedtogether end to end on a common axis for actuation in unison by a commonactuator shaft.

A primary object of the invention is to provide such a gangpotentiometer having means for adjusting the phase relationship betweenthe potentiometer units for facilitating incorporation of the gang in acomputer or other electronic circuit utilizing such a gang ofpotentiometer units actuated in unison.

In general, the invention contemplates a plurality of potentiometerunits each having its own individual casing in the form of a tubularsection of a common casing for the gang, the individual sections beingcoupled to one another for relative rotatable adjustment about theircommon axis, thus to adjust the phasing between the potentiometer units.Internal clamping is utilized in the coupling connections.

A particular object is to provide such a potentiometer wherein theadjustment can be eifected easily and simply by release pressure appliedto the heads of locking screw, accompanied by the application ofrotative torque to the adjoining sections between which adjustment is tobe effected.

A further object is to provide such a potentiometer wherein a fineadjustment can be attained.

Another object is to provide for a 360 degree range of phasingadjustment.

Another object is to minimize the effect of changes in temperature uponthe coupling connections between the potentiometer units. 7

Another object is to provide a gang potentiometer which may be readilyconverted to one embodying more or fewer units by a simple operation ofattaching or detaching units.

Other objects will become apparent in the ensuing specification andappended drawings in which:

Figure 1 is a side view, partially broken away and shown in section, ofa gang potentiometer embodying the invention;

Figure 2 is a transverse sectional view thereof, taken on the line 2-2of Figure 1;

Figure 3 is a transverse sectional view thereof, taken on the line 3-3of Figure 1; and

Figure 4 is an enlarged detail sectional view of the resistance coilmounting.

Referring now to the drawing in detail, and in particular to Figure 1, Ihave shown therein, as an example of one form in which the invention maybe embodied, a gang potentiometer embodying, in general, a front endpotentiometer unit A, succeeding units B, C and D coupled thereto, and arear end cap E closing the unit D.

Front end unit A and rear end cap E include end wall sections and 11,respectively, having counterbores in which are mounted bearings 12. Anactuator shaft 13 extends through front end wall section 10 and isjournalled in bearing 12. A conventional knob (not shown) may 2,859,319iatented Nov. 4, 1958 Units B, C and D include respective tubular casingsections 19 having respective annular shoulders 17 (Fig. 4), skirts 18'projecting axially therefrom at the outer diameter thereof, and neckmembers 20 at the inner di-.

ameter thereof, projecting axially in the opposite direction andtelescoped into the skirts 1 8, 18' of adjoining sections. The ends ofthe skirts are abutted against shoulders 21. The neck 20 and skirt 18 ofeach of the sections B, C, D are joined by an offset portion 22 definedbetween shoulders 17 and 21. Each neck member 20 has a cylindricalperipheral wall telescoped into the skirt portion 18 or 18 of anadjoining casing section with a fit that is sufiiciently snug tomaintain coaxial alignment of the casing sections and sufiiciently looseto allow free relative rotation of the adjoining casing sections subjectto the control of the clamping means hereinafter described.

Projecting axially from each neck member 20 is a plurality ofcircumferentially separated jaw segments 23 (preferably three 'or more)which have limited radial flexibility. The jaw segments 23 are ofreduced thickness, being offset radially inwardly of the outer diameterof intermediate neck member 23, and terminating in lips 24 that areheaded outwardly to a diameter normally slightly larger than (orapproximately the same as) the outer diameter of neck member 20, butadapted to be spread so as to enter an annular channel 25 within theadjoining skirt 18 or 18, and to lock against a frusto conical wall 26defining the adjacent side of such groove. The inclined surface of lip24, extending from its outer diameter toward the reduced portion of thejaw segment 23, coacts with the inclined wall 26 to effect a cammingaction for drawing the end of skirt 18 or 18 tightly against the opposedshoulder 21 when the jaw segments are expanded. Such jamming of the endsof the skirts against the adjoining shoulders, plus the grip of lips 24against walls 26, is effective to securely lock the casing sectionsagainst relative rotation.

For etfecting expansion of the jaw segments, I provide a series ofexpandible split ring actuators each including a body ring portion 27loosely received within a respective skirt 18 or 18', an integral flange28 of reduced outer diameter fitted loosely within an adjoining seriesof jaw segments 23 when unloaded, and a plurality (preferably three ormore) of screws 29 rotatably extended through a respective skirt 18 or18 and threaded into ring body 27. Screws 29, passing through openingsin skirt 18 or 18 with sufiicient circumferential clearance toaccommodate both expansion and contracting movements of the actuatorring, are operable, when rotated forwardly with their heads bearingagains the skirt body, to expand the actuator ring which, in turn, willexpand the jaw segments into clamping engagement with the co acting wall26. When the screws are backed off, the actuator ring restrains the jawsegments just sufficiently to maintain a connection resisting axialseparation of the casing sections 19 while allowing relative rotation topro vide for phasing adjustment. With the screws thus backed off toprovide radial clearance between their heads and the skirt body, theymay be engaged by the fingertips and, will transmit fingertip pressureto the actuator ring to contract it so as to release the jaw segments 23for withdrawal from the coupled skirt 18 or 18.

..Each of the potentiometer units A, B, C and D includes a toroidalresistance element 36 carried by a mounting ring 31 of L-section whichis mounted within a respective skirt 18 or 18 and axially positioned byabut ment against the adjoining shoulder 17 or 17. Ring 31 is lined withan insulator ring 32 providing a seat for resistance. element 30.

A" series of insulating hub elements 33, each encircled by aconductorcollar 34, are mounted on shaft 13 within the respective resistanceelements 3%. Each collar 34 carries a radial conductor arm 35 having anintegral outer end portion 36 extending axially and apertured to providea mounting for a conductor eyelet 37 in which is mounted a radiallydisposed brush or wiper fingerfifi. Brush 38 is tightly fitted in eyelet37 so as' to maintain adequate conducting contact with resistancecoil30; under thev light springloa'ding or arm portion 36, when adjustedprop'eriy againfstthe resistance coil, but can be adjusted axially inthe eyelet 37 by the application of pressure, untilithe" proper positionis attained. 'Such adjustment mayjbe utilized not only for initialsetting but also for wear'compensation.

' Each'skirt 18; 18 has an arcuate opening 39 over which 'is mounted'asaddle 40 of insulating material secured by screws 41 and mountingrespective terminal posts 42,43, 44. In terminal post 42 is mounted awiper whisker 45 which engages a respective collar 34 in an annulargroove 46 which restrains the Wiper from shifting axially. The wiper 45is deflected laterally so as to be tension-loaded against the collar tomaintain good conductive contact. Terminal posts 43, 44 are connected byconductors 47, 48 to respective ends of a respective resistance coil.Thus, the potentiometer units may be separately connected to respectiveunits of an electrical apparatus, for simultaneous operation.

Iclaim:

1. In a phasing gang potentiometer: a plurality of annular casingsections, arranged end-to-end, certain of said sections each including askirt at one end defining a counterbore, an intermediate neck ofsmaller'diameter at the other end, rotatably fitted within theskirt ofanadjoining section, and a circumferential array of circumatqrjringsandthe respective casing sections for expanding sai'd 'actu'at'or rings todeflect said jaws outwardly to cause said lipstoenter said'grooves andthereby couple saidjsections together and lock them in any selectedarrangement of'phasing. adjustment relative to one another.

'2; In a phasing gang potentiometer: a plurality of annular casingsections arranged end-to-end, and including end sections andintermediate sections, said intermediate sections each including a skirtat one end defining a counterbore, an intermediate neck of smallerdiameter at the other end, rotatably fitted within the skirt of anadjoining section, and acircurnferential array of circumferentiallyseparated flexible coupling jaws formed integrally with and projectingaxially from the neck and terminating. in radially outwardly projectinglips, the adjoining skirts having internal annular grooves positioned toreceive said lips; expansible split actuator rings disposed within therespective arrays of coupling jaws; actuator means acting between therespective actuator rings and the respective casing sections forexpanding said actuator rings to deflect said jaws outwardly to causesaid lips to enter said grooves and thereby couple said sectionstogether and lock them in any selected arrangement of phasing adjustmentrelative to one another; a common adjustment shaft journalled in saidend sections; wipers carried by said shaft and insulated therefrom;means providing separate conductor connections to the respective wipers;and respective resistor coils mounted in the respective casing sectionsand engaged by the respective wipers.

3. A potentiometer as defined in claim 2, wherein each casing sectionhas an external end shoulder formed as an offset between its neck andskirt and in end-abutting engagement with the skirt of the adjoiningsection.

4. A potentiometer as defined in claim 3, wherein. each of said annulargrooves has a frustoconical wall disposed toward the end of therespective skirt andeng-aged by the' jaw'lips of the adjoining.casingsection withv a camming action that is efiective to draw saidskirt end snugly against the abutting shoulder of the adjoining casingsection.

5. A potentiometer as defined in claim 1, wherein said actuator meanscomprise respective screws rotatably extending through respective skirtsand threaded into respective actuator rings to draw them outwardly.

. 6. In a phasing gang potentiometer: a'plurality of annularcasingsections arranged end-to-end and including end sectionsandintermediate.v section s, said intermediate sections'ea'ch includingaskirt at one .end defining a counterbore, an intermediate neck ofsmaller diameter at the other end, rotatably fitted within the-skirt ofan adjoining section,'an'd a circumferential arrayfof circumferentiallyseparated flexible coupling jaws formed integrally with and projectingaxially from thel neck and terminating in radially outwardly projectinglips, the. adjoining skirt having internal annular grooves positioned toreceive said lips; expansible split actuatonrings disposed vwithin therespective arrays of coupling jaws; actuator means acting between therespectiveact'uator rings and the respective casing sections forexpanding .saidactuator rings to deflect said jaws outwardly tocausejsaid lipsto enter said groovesandthereby couplesaidlsectionstogether and locking them in any selectedarrangement of phasingadjustment relative .to one another; ,faIcomnion adjustment shaftjournalledinthe end sections; wipers carried by said shaft and insulatedtherefrom;,n1eans pro viding separate conductor connectionstothe'respective wipers; respective resistorfcoilslmounted inther'espective casing sections and engaged by th'elrespective wipers;each of said intermediate casing sections having an internal endshoulder defined as an oflsetbetween the neck and skirt oftherespectivev section; and insulatormounting rings of L-section abutted.against theres'pective internal shoulders and providing seats for therespective resistor coils.

References Cited in the ,fileofthis patent UNITED STATES PATENT S-ll5,906 Stine June .13, 1871 1,767,226 Pearson June 24, 1930 2,747,230Burgess May 29, 1956

